The present invention relates to micro-electro-mechanical systems and, more particularly, relates to a micro-electro-mechanical system having a fully compliant four-link mechanism capable of improving the resolution of micro sensors and the displacement of micro actuators.
In the field of micro-electro-mechanical systems (MEMS) and other micro-mechanical applications, amplifying force or displacement output of an actuator and/or a transducer permits improvements in the performance of accelerometers, actuators, and transducers. Devices that amplify force or mechanical advantage typically achieve this at the expense of displacement or geometric advantage. Likewise, devices that amplify geometric advantage do so at the expense of mechanical advantage. By multiplying the force applied to a proof mass, the resolution and signal-to-noise ratio of an accelerometer can be improved. Moreover, some types of micro-actuators, such as thermal actuators, produce large force output, but very small displacement. By amplifying displacement, actuators become useful in many more applications, such as manipulating mirrors for micro-optical circuits.
Past efforts at increasing force output for MEMS have generally relied on simple levers or gears, resulting in a typical mechanical advantage of ten or twenty. However, significantly higher mechanical advantages are often necessary in a wide range of varying applications.
Accordingly, there exists a need in the relevant art to provide a device capable of amplifying either mechanical advantage or geometric advantage. Furthermore, there exists a need in the relevant art to provide a device capable of amplifying either mechanical advantage or geometric advantage while overcoming the disadvantages of the prior art.
According to the principles of the present invention, a micro-electro-mechanical system having an advantageous construction is provided. The micro-electro-mechanical system of the present invention improves the performance of micro-electro-mechanical accelerometers by amplifying the inertial force acting on a proof mass. This arrangement improves the resolution of the accelerometer thereby increasing the signal-to-noise ratio thereof. Similarly, by amplifying the motion of a micro-actuator, the present invention allows small-stroke, large-force actuators to produce useful motion. The micro-electro-mechanical system of the present invention is fully compliant, thus allowing it to work without friction, backlash, or wear and is easily manufactured using a single mask layer. Depending on these conditions, this device is capable of multiplying force inputs by as much as 23.7 and displacement inputs by as much as 588. Efficiency of these designs improves as the two objectives (mechanical and geometric advantage) are considered jointly in a multi-criteria optimization problem rather than individually. This arrangement allows dramatic improvement in existing devices, as well as enabling technologies to be pursued that previously have not yielded sufficient signal-to-noise ratios or have not demonstrated sufficient motion for usable actuation.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.